package org.apache.maven.settings.validation;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.maven.settings.Mirror;
import org.apache.maven.settings.Profile;
import org.apache.maven.settings.Repository;
import org.apache.maven.settings.Server;
import org.apache.maven.settings.Settings;
import org.apache.maven.settings.building.SettingsProblem.Severity;
import org.apache.maven.settings.building.SettingsProblemCollector;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.util.StringUtils;

/**
 * @author Milos Kleint
 */
@Component(role = SettingsValidator.class)
public class DefaultSettingsValidator implements SettingsValidator {

  private static final String ID_REGEX = "[A-Za-z0-9_\\-.]+";

  private static final String ILLEGAL_FS_CHARS = "\\/:\"<>|?*";

  private static final String ILLEGAL_REPO_ID_CHARS = ILLEGAL_FS_CHARS;

  public void validate(Settings settings, SettingsProblemCollector problems) {
    if (settings.isUsePluginRegistry()) {
      addViolation(problems, Severity.WARNING, "usePluginRegistry", null, "is deprecated and has no effect.");
    }

    List<String> pluginGroups = settings.getPluginGroups();

    if (pluginGroups != null) {
      for (int i = 0; i < pluginGroups.size(); i++) {
        String pluginGroup = pluginGroups.get(i).trim();

        if (StringUtils.isBlank(pluginGroup)) {
          addViolation(problems, Severity.ERROR, "pluginGroups.pluginGroup[" + i + "]", null, "must not be empty");
        } else if (!pluginGroup.matches(ID_REGEX)) {
          addViolation(problems, Severity.ERROR, "pluginGroups.pluginGroup[" + i + "]", null,
              "must denote a valid group id and match the pattern " + ID_REGEX);
        }
      }
    }

    List<Server> servers = settings.getServers();

    if (servers != null) {
      Set<String> serverIds = new HashSet<String>();

      for (int i = 0; i < servers.size(); i++) {
        Server server = servers.get(i);

        validateStringNotEmpty(problems, "servers.server[" + i + "].id", server.getId(), null);

        if (!serverIds.add(server.getId())) {
          addViolation(problems, Severity.WARNING, "servers.server.id", null,
              "must be unique but found duplicate server with id " + server.getId());
        }
      }
    }

    List<Mirror> mirrors = settings.getMirrors();

    if (mirrors != null) {
      for (Mirror mirror : mirrors) {
        validateStringNotEmpty(problems, "mirrors.mirror.id", mirror.getId(), mirror.getUrl());

        validateBannedCharacters(problems, "mirrors.mirror.id", Severity.WARNING, mirror.getId(), null,
            ILLEGAL_REPO_ID_CHARS);

        if ("local".equals(mirror.getId())) {
          addViolation(problems, Severity.WARNING, "mirrors.mirror.id", null,
              "must not be 'local'" + ", this identifier is reserved for the local repository"
                  + ", using it for other repositories will corrupt your repository metadata.");
        }

        validateStringNotEmpty(problems, "mirrors.mirror.url", mirror.getUrl(), mirror.getId());

        validateStringNotEmpty(problems, "mirrors.mirror.mirrorOf", mirror.getMirrorOf(), mirror.getId());
      }
    }

    List<Profile> profiles = settings.getProfiles();

    if (profiles != null) {
      Set<String> profileIds = new HashSet<String>();

      for (Profile profile : profiles) {
        if (!profileIds.add(profile.getId())) {
          addViolation(problems, Severity.WARNING, "profiles.profile.id", null,
              "must be unique but found duplicate profile with id " + profile.getId());
        }

        String prefix = "profiles.profile[" + profile.getId() + "].";

        validateRepositories(problems, profile.getRepositories(), prefix + "repositories.repository");
        validateRepositories(problems, profile.getPluginRepositories(), prefix + "pluginRepositories.pluginRepository");
      }
    }
  }

  private void validateRepositories(SettingsProblemCollector problems, List<Repository> repositories, String prefix) {
    Set<String> repoIds = new HashSet<String>();

    for (Repository repository : repositories) {
      validateStringNotEmpty(problems, prefix + ".id", repository.getId(), repository.getUrl());

      validateBannedCharacters(problems, prefix + ".id", Severity.WARNING, repository.getId(), null,
          ILLEGAL_REPO_ID_CHARS);

      if ("local".equals(repository.getId())) {
        addViolation(problems, Severity.WARNING, prefix + ".id", null,
            "must not be 'local'" + ", this identifier is reserved for the local repository"
                + ", using it for other repositories will corrupt your repository metadata.");
      }

      if (!repoIds.add(repository.getId())) {
        addViolation(problems, Severity.WARNING, prefix + ".id", null,
            "must be unique but found duplicate repository with id " + repository.getId());
      }

      validateStringNotEmpty(problems, prefix + ".url", repository.getUrl(), repository.getId());

      if ("legacy".equals(repository.getLayout())) {
        addViolation(problems, Severity.WARNING, prefix + ".layout", repository.getId(),
            "uses the unsupported value 'legacy', artifact resolution might fail.");
      }
    }
  }

  // ----------------------------------------------------------------------
  // Field validation
  // ----------------------------------------------------------------------

  /**
   * Asserts:
   * <p/>
   * <ul>
   * <li><code>string.length != null</code>
   * <li><code>string.length > 0</code>
   * </ul>
   */
  private boolean validateStringNotEmpty(SettingsProblemCollector problems, String fieldName, String string,
      String sourceHint) {
    if (!validateNotNull(problems, fieldName, string, sourceHint)) {
      return false;
    }

    if (string.length() > 0) {
      return true;
    }

    addViolation(problems, Severity.ERROR, fieldName, sourceHint, "is missing");

    return false;
  }

  /**
   * Asserts:
   * <p/>
   * <ul>
   * <li><code>string != null</code>
   * </ul>
   */
  private boolean validateNotNull(SettingsProblemCollector problems, String fieldName, Object object,
      String sourceHint) {
    if (object != null) {
      return true;
    }

    addViolation(problems, Severity.ERROR, fieldName, sourceHint, "is missing");

    return false;
  }

  private boolean validateBannedCharacters(SettingsProblemCollector problems, String fieldName, Severity severity,
      String string, String sourceHint, String banned) {
    if (string != null) {
      for (int i = string.length() - 1; i >= 0; i--) {
        if (banned.indexOf(string.charAt(i)) >= 0) {
          addViolation(problems, severity, fieldName, sourceHint,
              "must not contain any of these characters " + banned + " but found " + string.charAt(i));
          return false;
        }
      }
    }

    return true;
  }

  private void addViolation(SettingsProblemCollector problems, Severity severity, String fieldName, String sourceHint,
      String message) {
    StringBuilder buffer = new StringBuilder(256);
    buffer.append('\'').append(fieldName).append('\'');

    if (sourceHint != null) {
      buffer.append(" for ").append(sourceHint);
    }

    buffer.append(' ').append(message);

    problems.add(severity, buffer.toString(), -1, -1, null);
  }

}
